Multimedia messaging method and system

ABSTRACT

A multimedia messaging method and system, wherein the same multimedia message can be used to encapsulate both non-streamable media components and descriptors relating to streamable media components. A recipient extracts the descriptors from the multimedia message and initiates streaming sessions accordingly. The notification process by which a recipient user agent is informed of the availability of a multimedia message is the same regardless the type of the components within the message.

[0001] This invention relates to data transmission. More specifically,the invention relates to the streaming of media content in a MultimediaMessaging Service.

[0002] In mobile communications networks, the term Multimedia MessagingService (MMS) is commonly used to describe a new approach fortransmitting messages having multimedia content. The MultimediaMessaging Service allows messaging between different mobile users and/orbetween mobile users and the Internet. There is an already agreedsolution for providing an MMS in 3^(rd) Generation mobile communicationnetworks and its features are described in 3^(rd) Generation PartnershipProject (3GPP) Technical Specification (TS) 23.140, V.4.1.0 “MultimediaMessaging Service (MMS), Functional Description, Stage 2 (Release 4,2000-12)”. The Multimedia Messaging Service proposed in 3GPP TS 23.140,release 4 employs a store-and-forward approach to message delivery.Multimedia messages are constructed in such a way that the mediacontent, information necessary to describe the media content andaddressing information, identifying the intended receiver of themessage, are encapsulated together. The multimedia message is then sentfrom a sending MMS user agent to a Multimedia Messaging Service CentreMMSC, which in turn notifies the intended receiver (recipient MMS useragent) about the message. Later on, the multimedia message is downloadedby the recipient MMS user agent terminal as a whole and only presentedto the user once downloaded and stored in the recipient MMS user agent.

[0003] Next, the structure and operation of a typical MMS system will bedescribed with reference to FIGS. 1, 2 and 3.

[0004]FIG. 1 shows an overview of MMS system elements according to 3GPPTS 23.140. The system comprises the following items:

[0005] a plurality of MMS user agents (UAs) 110, each of which iscapable of transmitting and receiving multimedia messages;

[0006] a roaming MMS user agent 127;

[0007] Access networks 122,124 and 126 of different types including:

[0008] A second generation mobile telecommunications network 122 such asa GSM phase 2 network;

[0009] A third generation mobile telecommunications network 124 such asa Universal Mobile Telecommunications System (UMTS); and

[0010] A mobile access network 126, for example a wireless-LAN network.

[0011] The Internet (or another Internet Protocol (IP)-network) 130,having an external server 134, such as an e-mail server, and a wiredE-mail client 132;

[0012] A Multimedia Messaging Service relay 142 and an MMS server 144which, in this example, are integrated into a single unit, referred toas a Multimedia Messaging Service Centre (MMSC) 140, but which canalternatively be implemented as separate or distributed entities;

[0013] A message store 150 in connection with the MMS server 144; and

[0014] User databases 160 comprising, for example, user subscription andaddressing information.

[0015] The collective term Multimedia Messaging Service Environment(MMSE) is used to describe those functional elements that operatetogether to implement a multimedia messaging service. In FIG. 1, an MMSEis formed by the elements within the oval outlined region.

[0016] Referring in further detail to FIG. 1, each MMS user agent 110connects to the MMS relay 142 through its access network 122, 124. Theroaming MMS user agent 127 connects to the MMS relay 142 through themobile access network 126 and via the Internet 130. The MMS relay isconnected to the MMS server 144 and to the user databases 160.Furthermore, the external server 134 and the wired E-mail client 132 areconnected to the Internet 130.

[0017]FIG. 2 shows an overview of interworking between different MMSE'saccording to 3GPP TS 23.140. The communication of multimedia messagestakes place between user agents 110A (sender) and 110B (recipient) whichreside in two different Multimedia Messaging Service Environments. Forsimplicity and clarity, the two Multimedia Messaging ServiceEnvironments, MMSE A and MMSE B, are each shown to comprise a single MMSrelay, linked to a single MMS server, thus forming two MMSC's 214 and224. It should be appreciated that in a practical MMSE, the number ofMMS relays and servers may be, and typically will be, greater than this.MMSE A and MMSE B may, for example, have different operators, differentgeographical locations or coverage areas and/or differ in terms of theirtechnical characteristics and capabilities. Furthermore, in thesituation where a particular MMSE comprises more than one MMS relay, themethod according to the invention can also be applied within the MMSE.In the example shown in FIG. 2, both MMS user agents 110A and 110B aredepicted as devices that communicate with their respective MMSE 210, 220via a radio communication network 212, 222. However, it should beappreciated that either MMSE user agent A or MMSE user agent B, or bothof them, could reside in a fixed line network (not shown).

[0018] In connection with FIG. 2, it will be assumed that MMS user agentA 110A, which has subscribed to the multimedia messaging serviceprovided in Multimedia Messaging Service Environment A 210, wishes tosend some media content to MMS user agent B 110B, which has asubscription to the multimedia messaging service provided in MMSE B 220.In general, the content of a multimedia message can comprise a varietyof components, some of which are suitable for streaming and othercomponents which are not typically suitable for streaming, such as textor still images. In the following example, which describes the creation,transmission and retrieval of a multimedia message, it will be assumedthat all the components of the message are non-streamable content types.The current provisions for streaming download of multimedia messagecomponents provided by 3GPP TS 23.140 will then be consideredseparately.

[0019] Referring once more to FIG. 2, when initiating the communicationof a multimedia message to MMS user agent B, MMS user agent A firstselects the media content to be transmitted. For example, the mediacontent may take the form of a still image and some associated text,stored in the memory of user agent

[0020] A. The image may have been recorded, for example, using a camera,and still image encoding equipment built into user agent A.Alternatively, the image and text may already have been downloaded fromanother source to user agent A. In either case, user agent Aencapsulates the media content as a multimedia message, comprising themedia content itself, information necessary to describe the mediacontent and addressing information, identifying the intended recipientof the message. MMS user agent A then sends the message to MMS relay Athrough radio network A 212.

[0021] On receiving the multimedia message, MMS relay A determines, fromthe addressing information included with the message, that the intendedrecipient is not a user agent of MMSE A, but a user agent of MMS relay Band forwards the multimedia message to MMS relay B. Routing of themultimedia message to the correct MMS relay, i.e. that responsible forMMS user agent B is achieved, for example, using standardised mechanismsprovided for in the existing 3GPP multimedia messaging solution. Onreceiving the multimedia message, MMS relay B stores the media contentin MMS server B and sends a notification to the intended recipient, MMSuser agent B, thereby indicating that a multimedia message has arrivedand its content is available to be downloaded from MMS relay B. Inresponse to receiving the notification, MMS user Agent B retrieves themedia content from (via) the MMS relay B. The retrieval of the mediacontent is initiated by signalling with MMS relay B.

[0022]FIG. 3 illustrates the process of notification and multimediamessage retrieval in more detail. Specifically, FIG. 3 shows the flow ofmessages that takes place when MMS relay B receives an MMS messageintended for recipient MMS user agent B. MMS relay B receives the MMSmessage, stores it in MMS server B, and then informs MMS user agent B ofthe arrival of the message using an MMS notification message 310(MM1_notifcation.REQ in 3GPP TS 23.140).

[0023] Next, the MMS user agent B responds with an MMS notificationresponse 320 (MM1_notifcation.RES in 3GPP TS 23.140) to acknowledgereceipt of the MMS notification 310.

[0024] Having received the MMS notification message 310, MMS user agentB is aware that a multimedia message is available for retrieval and mayinitiate a process to download the message. This may be donesubstantially as soon as the notification message is received, or may beperformed at some later time. When MMS user agent B desires to startdownloading the MMS message, it sends an MMS retrieve request 330(MM1_retrieve.REQ) to MMSC B 224. MMSC B 224 responds by retrieving themultimedia message from MMS server B and sends an MMS retrieve response340 (MM1_retrieve.RES in 3GPP TS 23.140) to MMS user agent B. In thecase of a multimedia message that comprises only non-streamablecomponents, as considered in this example, the MMS retrieve responsemessage carries the actual multimedia message components to bedownloaded. After receipt of the entire multimedia message, the MMS useragent B sends an MMS acknowledgement 350 (acknowledging the receipt ofthe entire multimedia message) to the MMS relay B.

[0025] As mentioned earlier, some media components may be suitable fordownloading by streaming. The term “streaming” is generally used todescribe the presentation of media content, for example an audio orvideo clip, or a combination of different media types, in a continuousway while the content is being transmitted to a recipient over a datanetwork. A “stream” can be a flow of data enabling the recipient topresent some continuous flow of information such as motion pictures(i.e. video), voice or music. In a typical video stream, some 10 to 20video frames are transmitted per second. In practice, streaming can beeither live (real-time) or performed in an on-demand fashion. The term“live streaming” describes the creation of a media stream from a livesource, for example a stream of digital images produced by a videocamera, while the term “on-demand streaming” describes the creation of amedia stream from, for example, a file stored on a server.

[0026] The application of streaming in mobile networks looks verypromising, especially considering the fact that mobile terminalstypically have limited multimedia playing resources such as memory andprocessing power. In general, the adoption of a streaming approach tomedia download and presentation has the potential to reduce the amountof available memory required by mobile terminals

[0027] Recently, interest has also arisen in the incorporation ofstreaming into the proposed 3rd generation multimedia messaging service.However, as mentioned earlier, the MMS service is based on theencapsulation of media content, message description and addressinginformation into a single message. This kind of encapsulation isincompatible with the streaming of media content and therefore certainmodifications to the MMS service recommendations are necessary in orderto accommodate the streaming download of media content. 3GPP TS 23.140,release 4 allows a streaming session to be established between arecipient user agent and a recipient MMS relay, but requires that thenotification message sent from the recipient MMS relay to the recipientMMS user agent be modified to a certain extent.

[0028] According to the recommendation, if a recipient MMS relay, suchas MMS relay B described in the above example, receives a multimediamessage containing streamable media content, it forms a modified MMSnotification message and sends it to the intended recipient user agentto notify it about the streamable multimedia components. The modifiednotification message contains information necessary to initialise astreaming session between the recipient MMS user agent and an MMS serverthat has access to the streamable multimedia components.

[0029] Thus, according to 3GPP TS 23.140, release 4, the standard MMSnotification message, used to inform an intended recipient user agentthat a multimedia message is available for download, must be modified insuch a way as to provide particulars of a streamable multimediacomponent to be downloaded. This enables the recipient user agent toestablish a streaming session to download the multimedia component.

[0030] However, despite this modification, there is still no mechanismavailable in the MMS specification to enable the downloading of bothstreamable and non-streamable multimedia components in a consistentmanner. There is need for such a capability, because it would be usefulto be able to receive both non-streamable multimedia components, such asstill pictures and text or program applets together with streamablemultimedia components such as sound, voice or video streams.

[0031] According to a first aspect of the invention there is provided amethod for receiving a multimedia message, comprising the steps of:

[0032] receiving a multimedia message transmission;

[0033] separating from the multimedia message transmission a descriptorcontaining information necessary to initiate a streaming session; and

[0034] initiating a streaming session, using the descriptor, to retrievea stored streamable media component described by the descriptor.

[0035] Preferably, the method further comprises the step of separating anon-streamable media component from the multimedia message transmission.

[0036] According to a second aspect of the invention there is provided amethod for multimedia messaging, comprising the steps of:

[0037] storing a multimedia message containing a streamable mediacomponent in a communications network entity;

[0038] sending a multimedia message transmission from the network entityto a recipient user agent; and

[0039] including in said multimedia message transmission a descriptorproviding information allowing the recipient user agent to initiate astreaming session to retrieve the streamable media component.

[0040] The invention provides the advantage of allowing transmission ofstreamable media components using communication systems according theexisting MMS specifications with only minor modifications.

[0041] Preferably, with the same multimedia message, both streamable andnon-streamable components may be sent from an originator to a recipientby using the descriptor before downloading the multimedia message.

[0042] Preferably, the method further comprises notifying a recipientuser agent that a message is available using a notification message.Preferably the notification message conforms to MMS specifications.

[0043] Furthermore, the invention allows the use of a single type ofnotification message to inform a recipient MMS user agent that amultimedia message is available for download. In other words, a singlenotification message type may be used regardless of the media content ofa particular multimedia message. This has the advantage of simplifyingthe formation of notification messages and allowing the availability ofmultimedia messages for download to be indicated in a consistent manner.

[0044] Preferably, a streamable media component of a multimedia messagecomprising both a non-streamable and a streamable media component isreplaced with the aforementioned descriptor, such that the multimediamessage is modified to contain the non-streamable components and thedescriptor. Thus, when the modified message, containing thenon-streamable component and the descriptor is downloaded to therecipient user agent, the user agent can use the information provided bythe descriptor to initiate a streaming session to download thestreamable media component.

[0045] In a situation where a multimedia message contains more than onestreamable media component, each streamable media component isadvantageously replaced with a corresponding descriptor. Alternatively,the descriptor contains information relating to at least two or allstreamable media components. The descriptor is then provided in themultimedia message in place of all the streamable media components,which it describes.

[0046] Preferably, this replacement is performed either by a recipientMMS relay or MMS server. In other words, the replacement is preferablyperformed by the MMS relay or MMS server associated with the recipientuser agent. Alternatively, another communication block such as a proxyserver can perform the replacement.

[0047] Preferably, the descriptor is selected from a group consistingof: a session description file, a Uniform Resource Locator (URL), and aUniversal Resource Identifier (URI).

[0048] Preferably, the session description file is a session descriptionprotocol (SDP) file.

[0049] Preferably, the session description file contains all the datanecessary to initiate a streaming session to download a streamable mediacomponent.

[0050] The inclusion of the descriptor in the multimedia messagetransmission makes it unnecessary to separately transmit the data toinitiate the streaming session. This spares communication bandwidth andaccelerates the messaging, as excessive messaging can be avoided.Furthermore, should the recipient user agent reject the message, nodescriptor needs to be sent in vain.

[0051] According to a third aspect of the invention there is provided amultimedia messaging user agent comprising:

[0052] a transceiver for receiving a multimedia message and forestablishing a streaming session; characterised by the user agentfurther comprising:

[0053] a processor for searching the multimedia message for a descriptorcontaining streaming initialisation data; and

[0054] the processor being arranged to control the transceiver toinitiate a streaming session using the streaming initialisation datacontained by the descriptor.

[0055] According to a fourth aspect of the invention there is provided amultimedia messaging service system comprising:

[0056] a first network entity for storing a multimedia message;

[0057] a plurality of user agents;

[0058] a second network entity for notifying a user agent of a messageavailable to the user agent, said user agent being a recipient useragent;

[0059] a third network entity for searching the multimedia message for astreamable media component, for storing such a component of themultimedia message, and for modifying the multimedia message by placinga descriptor in the multimedia message, sufficient to allow therecipient multimedia user agent to initiate a streaming session toretrieve the streamable media component;

[0060] the second network entity being arranged to receive a request fordelivering the multimedia message to the recipient user agent and totransfer the multimedia message to the recipient user agent in responseto said request.

[0061] The second and third network entities may be the same, forexample a multimedia relay. Alternatively, they may be differententities.

[0062] According to a fifth aspect of the invention there is provided amultimedia message comprising an address of the recipient of themultimedia message; characterised in that the multimedia message furthercomprises:

[0063] a descriptor containing information necessary for allowing arecipient user agent, using the descriptor, to initiate a streamingsession to retrieve at least one streamable media component.

[0064] According to a sixth aspect of the invention there is provided acomputer program product for controlling a multimedia messaging useragent, comprising:

[0065] computer executable program code to enable the user agent toreceive a multimedia message;

[0066] characterised by the computer program product further comprising:

[0067] computer executable program code to enable the user agent tosearch the multimedia message for a descriptor containing streaminginitialisation data; and

[0068] computer executable program code to enable the user agent toinitiate a streaming session using the streaming initialisation datacontained by the descriptor.

[0069] The invention will now be described, by way of example only, withreference to the accompanying drawings, in which:

[0070]FIG. 1 shows an overview of MMS system elements according to 3GPPTS 23.140, v. 4;

[0071]FIG. 2 shows an overview of interworking MMS system elementsaccording to 3GPP TS 23.140, v. 4;

[0072]FIG. 3 shows the flow of messages between a receiving MMSrelay/MMS server and a recipient MMS user agent;

[0073]FIG. 4 shows the flow of messages between a receiving MMSrelay/MMS server and a recipient MMS user agent, according to apreferred embodiment of the present invention;

[0074]FIG. 5 shows a flow chart describing the operation of an MMSrelay, according to a preferred embodiment of the present invention; and

[0075]FIG. 6 shows a block diagram of the structure of an MMS useragent, according to the preferred embodiment of the present invention.

[0076] FIGS. 1 to 3 have been described in the foregoing to illustratethe prior art. They also form a framework within which the presentinvention can be implemented. A preferred embodiment of the inventionwill next be described with reference to the operation of an MMS systemon receiving a multimedia message containing streamable- andnon-streamable components. An example implementation of an MMS systemthat supports the preferred embodiment will also be described. Thepreferred embodiment of the present invention is based on replacing astreamable multimedia component of a multimedia message with adescriptor that provides information allowing a recipient MMS user agent110B to initiate a streaming session to download the streamablecomponent. As previously described, until now streaming in connectionwith MMS has only been possible by altering the MMS notification message310. In the preferred embodiment of the present invention, thedescriptor is embedded in the multimedia message and is received by arecipient user agent just as any other multimedia component in the MMSretrieve response. The user agent extracts the information provided bythe descriptor, which can then be used to initiate a streaming sessionto download the streamable component. This means that it is no longernecessary to modify the MMS notification message 310.

[0077]FIG. 4 shows the flow of messages that takes place between arecipient MMSC and a recipient MMS user agent, according to thepreferred embodiment of the present invention. After arrival of amultimedia message at the MMSC, messages 310 to 330 are first exchanged.This happens in a manner equivalent to what takes place in aconventional MMS system when there are no streamable components in areceived multimedia message. The modifications introduced by the presentinvention affect the signalling that takes place after the MMS retrieverequest 330. According to the preferred embodiment, if the receivedmultimedia message comprises a streamable media component in addition toa non-streamable media component, the MMS retrieve response 340 containsthe non-streamable multimedia message component and a descriptordescribing the streamable multimedia component. According to thepreferred embodiment, in a situation where the multimedia messagecontains more than one streamable media component, each streamable mediacomponent is replaced with a separate descriptor, each descriptorcomprising information sufficient to allow the recipient user agent 110Bto initiate a streaming session for receiving the streamable mediacomponent in question.

[0078] If the multimedia message contains only streamable components,then the multimedia message will only contain descriptors of streamablecomponents.

[0079] Typically, the descriptors are arranged in form of a sessiondescription file, such as a Session Description Protocol (SDP) document,which is included within the MMS message. The actual file structure canbe implemented in various manners, but according to the preferredembodiment, a structure such as that shown in Wireless ApplicationProtocol WAP Multimedia Messaging Service Version 1.0, MessageEncapsulation Draft 0.8 (17-Feb.-2000), FIG. 2 is used. It isadvantageous to arrange the multimedia message such that the descriptoris delivered in the early part of the MMS message so that the streamingsession(s) can be initiated without large delays, after downloading ofthe MMS message has commenced.

[0080] In an alternative embodiment, a shared session description filecontains descriptions of two or more downloadable multimedia components.

[0081] The session description file provides a description of thepresentation for a particular streamable multimedia component and allowsthe recipient to accomplish the media intialisation part of thestreaming process. An SDP file is a good example of a widely usedsession description file type. SDP has an Internet Assigned NumbersAuthority (IANA) registered Multi-purpose Internet Mail Extensions(MIME) type to be mentioned as the content type of the component of theMMS Retrieval Response message 340.

[0082] Advantageously, the session description file contains thefollowing data: a protocol version, information about the owner and/orcreator of the media content, a session identifier, a session name andattributes, session information, an originator identifier, such as thee-mail address or phone number of the sender of the message, connectioninformation, bandwidth information, different time-related information,and a title and attribute for each media component described by thesession description file. The session description file may furthercomprise some cryptographic information, such as a MessageAuthentication Code (MAC), a cryptographic checksum for checking thevalidity of the content, or a challenge for allowing the recipient MMSuser agent to generate a session key to be used for decrypting orvalidating the content.

[0083] In alternative embodiments, other forms of files are used forthis purpose. TEXT, RTSL and MHEG are some other example files to beused for this purpose and all these files have a registered MIME type.

[0084] The streaming session is implemented according to commonly usedstreaming protocols. The Real Time Streaming Protocol (RTSP) is awell-known session layer protocol in this regard. The Real TimeProtocol/Real Time Control Protocol (RTP/RTCP) are designed to controlthe transport of streaming content, while the user datagram protocol(UDP) and/or transmission control protocol (TCP) can be used astransport protocol for streaming.

[0085] The use of separate session description files provides theadvantage of more flexible use, since different network entities mayreplace different streamable multimedia components with respectivedescriptors.

[0086] The multimedia message, that is, the content, can be up loaded tothe MMSC either by streaming or by any other appropriate method. In thepreferred embodiment of the present invention, use of streaming indownloading media content to a given recipient is independent of themanner in which the content was uploaded to the MMS relay B.

[0087]FIG. 5 shows a flow chart describing the operation of a recipientMMS relay according to the preferred embodiment of the presentinvention. The operation starts from block 502. Next, the MMS relay Breceives a multimedia message (block 504). The MMS relay checks whetherthe multimedia message contains any streamable media components (block506). If it does, each streamable media component is stored (block 508)and a descriptor appropriate for the component in question is formed andincluded in the multimedia message in place of the media componentitself (block 510). In the next step of the operation, the recipient MMSuser agent is notified (MMS notification) that the multimedia message isavailable (block 512).

[0088] After receiving notification of an available multimedia message,the recipient MMS user agent should acknowledge the notification bysending an MMS notification response message. The MMS relay checks if ithas received the MMS notification response (block 514). If not, the MMSrelay checks whether the message has expired (block 515). If the messagehas not expired, the relay attempts to notify the recipient again, forexample, after a predetermined time period has elapsed. If the messagehas expired, the MMS relay will not attempt to notify the recipient useragent again and advantageously clears the message (block 520), that is,erases the stored media components related thereto.

[0089] If a notification response is received (block 514), the operationproceeds by checking for the receipt of an MMS retrieve request (block516). In the preferred embodiment of the invention, the MMS retrieverequest can be integrated with the notification response, if both ofthese would otherwise be transmitted within a short period of time (forexample, 1, 5 or 10 minutes), or if automatic downloading of incomingmultimedia messages has been selected.

[0090] If the retrieve request has not been received, the MMS relaychecks whether the multimedia message has expired (block 518). If ithas, the operation proceeds to block 520 and the multimedia message iscleared as explained above. If the multimedia message has not expired,the operation proceeds to block 522. There the multimedia message, nowcontaining a descriptor for each streamable multimedia component, istransmitted to the recipient MMS user agent. After transmission of themultimedia message, the message is cleared (block 524) if it is notneeded for transmission to another recipient (e.g. in the case ofmulticasting). Typically, the message is cleared only after anacknowledgement of receipt has been received from the recipient MMS useragent.

[0091] Typically, an MMS relay is implemented as a server computer andis controlled by a computer program, which enables the MMS relay tooperate according to the aforementioned steps.

[0092]FIG. 6 shows the structure of an MMS user agent according to thepreferred embodiment of the present invention in which the MMS useragent is implemented in a wireless communication device. Amicroprocessor μP controls the blocks responsible for the MMS useragent's different functional blocks. These functional blocks comprise arandom access memory RAM, a radio frequency block RF, a read only memoryROM, an input/output port I/O for external connections, a user interfaceUI, having an audio system SND and a display DPL for presentingmultimedia messages and a keyboard KBD for receiving data and commandsfrom a user. The microprocessor's operating instructions, that isprogram code and the MMS user agent's basic functions are stored inadvance, for example during the manufacturing process, in the ROM. Inaccordance with its program, the microprocessor uses the RF block fortransmitting and receiving messages on a radio path. The microprocessormonitors the state of the user interface UI and controls the MMS useragent according to the program code. On receiving a multimedia message,the microprocessor μP examines the message for a descriptor of astreamable multimedia component. If it finds a descriptor, it initiatesa streaming session accordingly for retrieving, or down streaming, acorresponding multimedia component. If more than one descriptor isfound, a corresponding number of streaming sessions are initiated fordown streaming the respective multimedia components.

[0093] Typically, the streaming sessions are set up substantiallyimmediately, but alternatively, the descriptor information can also bestored in the random access memory RAM and used at some later time toinitiate a streaming session.

[0094] If a particular multimedia component is of a type not supportedby the MMS user agent itself, the microprocessor may control theinput/output port I/O to forward such a component to an external devicethat supports that type of multimedia component. Such an external devicemay be a personal computer, typically a laptop computer. This alsoprovides the advantage of allowing use of enhanced user interface andsound capabilities, if the external device provides such facilities. Theinput/output port may be an infrared port, a wired port, or a Low PowerRadio Frequency connection port such as a Bluetooth port.

[0095] In case of a streamable multimedia component, the descriptorinformation can be passed to such an external device to enable thatexternal device to establish a streaming session, either via the MMSuser agent or via another route, such as fixed Internet access.

[0096] Advantageously, the MMS relay has access to a user profile of therecipient user agent stored in the user databases 160. Using theprofile, it can determine whether each of the multimedia components of amultimedia message conforms to the capabilities of the recipient useragent and/or preferences defined the recipient user agent's userprofile. If necessary, the multimedia components of excessive qualitymay be down-converted to a lower, but sufficient quality level, suchthat their transmission is faster and they can be readily used by therecipient user agent without any further conversion or manipulationbefore presentation to the user. Similarly, multimedia components may beconverted from one media format to another, such that the resultconforms to the capabilities and/or preferences of the recipient useragent. The conversion may be made either beforehand or on/duringtransmission of the MMS retrieve response. Particular implementationsand embodiments of the invention have been described. It is clear to aperson skilled in the art that the invention is not restricted todetails of the embodiments presented above, but that it can beimplemented in other embodiments using equivalent means withoutdeviating from the characteristics of the invention. The scope of theinvention is only restricted by the attached patent claims.

1. A method for receiving a multimedia message, comprising the steps of:receiving a multimedia message transmission; separating from themultimedia message transmission a descriptor containing informationnecessary to initiate a streaming session; and initiating a streamingsession, using the descriptor, to retrieve a stored streamable mediacomponent described by the descriptor.
 2. A method according to claim 1,further comprising: separating a non-streamable media component from themultimedia message transmission.
 3. A method for multimedia messaging,comprising the steps of: storing a multimedia message containing astreamable media component in a communications network entity; sending amultimedia message transmission from the network entity to a recipientuser agent; and including in said multimedia message transmission adescriptor providing information allowing the multimedia user agent toinitiate a streaming session to retrieve the streamable media component.4. A method according to any of the preceding claims, the method furthercomprises notifying a recipient user agent that the multimedia messageis available using a notification message.
 5. A method according to anyof the preceding claims, wherein the multimedia message further containsa non-streamable media component and the multimedia message transmissionfurther contains the non-streamable media component.
 6. A methodaccording to any of the preceding claims, wherein a streamable mediacomponent of a multimedia message is replaced with the aforementioneddescriptor, such that the multimedia message is modified to contain thedescriptor.
 7. A method according to claim 6, wherein, if the multimediamessage contains more than one streamable component, each streamablecomponent is replaced with a corresponding descriptor.
 8. A methodaccording to any claims 3 to 6, wherein, if the multimedia messagecontains more than one streamable component, at least two streamablecomponents are replaced with one descriptor common for all replacedcomponents.
 9. A method according to any of claims 6 to 8, whereinreplacement is performed by an entity selected from a group consistingof the following: a recipient MMS relay, a recipient MMS server, and anintermediate communication block.
 10. A method according to any of thepreceding claims, wherein the descriptor is selected from a groupconsisting of: a session description file, a uniform resource locator(URL), and a Universal Resource Identifier (URI).
 11. A method accordingto claim 10, wherein the session description file is a sessiondescription protocol (SDP) file.
 12. A method according to any of thepreceding claims, wherein the descriptor contains all the data necessaryto initiate a streaming session to download the streamable component.13. A multimedia messaging user agent comprising a transceiver (RF) forreceiving a multimedia message and for establishing a streaming session;characterised by the user agent further comprising: a processor (CPU)for searching the multimedia message for a descriptor containingstreaming initialisation data; and the processor (CPU) being arranged tocontrol the transceiver (RF) to initiate a streaming session using thestreaming initialisation data contained by the descriptor.
 14. Amultimedia messaging service system (100) comprising: a first networkentity (150) for storing a multimedia message; a plurality of useragents (110,127); a second network entity (142) for notifying a useragent of a multimedia message available to the user agent, said useragent being a recipient user agent; a third network entity (142,144) forsearching the multimedia message for a streamable media component, forstoring such a component, and for modifying the multimedia message byplacing into the multimedia message, instead of the streamablecomponent, a descriptor sufficient to allow the recipient multimediauser agent (110,127) to initiate a streaming session to retrieve thestreamable media component; the second network entity (142) beingarranged to receive a request for delivering the multimedia message tothe recipient user agent (110,127) and to transfer the multimediamessage to the recipient user agent responsive to the request.
 15. Amultimedia message comprising an address of a recipient of themultimedia message; characterised in that the multimedia message furthercomprises: a descriptor containing all necessary data for allowing arecipient user agent, using the descriptor, to initiate a streamingsession to retrieve at least one streamable media component.
 16. AComputer program product for controlling a multimedia messaging useragent, comprising computer executable program code to enable the useragent to receive a multimedia message; characterised by the computerprogram product further comprising: computer executable program code toenable the user agent to search the multimedia message for a descriptorcontaining streaming initialisation data; and computer executableprogram code to enable the user agent to initiate a streaming sessionusing the streaming initialisation data contained by the descriptor.